Toshiba MMD-AP0726HP-UL Service Manual page 71

Check code
Outdoor 7-segment display
Main
remote
Check
Sub-code
control
code
Detected outdoor unit No.
P19 P19
P20 P20 –
Location
of Description System status
detection
I/F 4-way valve All stop
reversing trouble
I/F Activation of All stop
high-pressure
protection
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Trouble detection
condition(s)
Abnormal refrigerating cycle • Check for defect in main
data is collected during
heating operation. • Check for coil defect in 4-
• Check resistance
• Check output voltage
• Check for wiring trouble
<During cooling operation>
• Check for defect in Pd
Pd sensor detects pressure
equal to or greater than
• Check service valves (gas
558psi (3.85MPa)
<During heating operation>
Pd sensor detects pressure
• Check for defect in outdoor
equal to or greater than
522psi (3.6MPa)
• Check for defect in outdoor
• Check outdoor PMV
• Check indoor/outdoor heat
• Check for short-circuiting
• Check SV2 circuit for
• Check for defect in outdoor
• Check for defect in indoor
• Check opening status of
• Check indoor-outdoor
• Check for faulty operation
• Check gas balancing SV4
• Check SV5 valve circuit.
• Check for refrigerant
Check items (locations)
body of 4-way valve.
way valve and loose
connection of its
connector.
characteristics of TS1
and TE1,TE2 sensors.
characteristics of Pd and
Ps pressure sensors.
involving TE1 and TL1
sensors.
pressure sensor.
side, liquid side) to confirm
full opening.
fan.
fan motor.
(PMV1, 3, 4) for clogging.
exchangers for clogging.
of outdoor suction/
discharge air flows.
clogging.
P.C. board (I/F).
fan system (possible cause
of air flow reduction).
indoor PMV.
communication line
for wiring trouble.
of check valve in discharge
pipe convergent section.
valve circuit.
overcharging.